This application claims the priority of application 197 15 072.1, filed in Germany on Apr. 11, 1997, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a wheel for a motor vehicle with a wheel spider and a rim, each formed by a shell part, and having hollow spokes between them as well as walls with air openings, said spider and rim being capable of being connected permanently with one another.
German application number 196 01 778.5, describes a wheel that consists of two shell parts, for example a wheel spider and a rim well. These two shell parts are partially inserted into one another and connected together in areas in which they are in contact, for example by welds. In particular, there is a circumferential connection in the vicinity of the air openings in the two shell parts.
A goal of the invention is to provide a wheel for a motor vehicle that consists of two shell parts, said parts being designed precisely for connection in simple fashion, and in particular can be fitted into one another in the vicinity of the air openings.
This goal is achieved according to the invention by providing a wheel of the above-noted type, wherein the air openings of a rim are covered by a cast web that can be punched.
Primary advantages achieved by the invention consist essentially in that a dimensionally exact air opening is formed in the shell part of the rim by providing a cast web in the air openings of the rim, said openings being produced in the course of the casting of the rim, and a subsequent mechanical punching of this web. The air openings have a metallically clean edge suitable for welding to the other shell part. In addition, the tolerances for the size of the air opening are limited and a precise fit is achieved for the wall of the other air opening in the shell part of the wheel spider. As a result, problem-free welding can be performed, using an electron-beam welding process or other welding processes for example.
The cast web preferably has a smaller thickness than the wall of the shell part of the rim in this area and lies flush with at least one surface of the rim. In addition, only one edge bordering the air opening is possible, which is then punched out to form the dimensionally precise air opening. Preferably the cast web is designed to lie flush with the inner surface of the shell part of the rim, with the web being made thinner than the wall of the shell and producing a depression in the outer surface.
The web is preferably punched out using a tool that has a plurality of punches whose number corresponds to that of the air openings, said punches acting against pressure pads. The adjoining walls of the shell part of the rim at the pressure pad are designed to abut the pressure pad somewhat and are each spaced away from the edge of the air opening. In addition, a milling method or laser cutting method can also be used to cut out the web.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.